Hi All, I have a question on license for plugins. I found that some plugins are AGPL. If I use such a plugin in my meltano project, does it mean that my projects becomes AGPL as well?

Hi Marcin, a complex question. Hopefully a simple answer. GPL - yes, you must extend the open source rights to your users. AGPL - no, you don’t need to open source your code, but you cannot use that AGPL library as part of a hosted service. https://choosealicense.com/licenses/

So, I modified the plugin by making a public fork on github. So this satisfies the license I believe.

All good for you. Use in a project in your company is 100% ok - you can have private forks of the original repo too. Not exactly in the spirit of open source perhaps, but fine all the same. To be clear, use of GPL in your company software stack is ok too. All because you are not distributing the software. If you are a software company, who is distributing software, then you need to worry more about the distribution implications of licencing. Read on for some interesting AGPL: The idea behind the AGPL License was to address the “application service provider (ASP) loophole,” which both Henry Poole and Stallman believed existed in the GPL. The ASP loophole meant that software-as-a-service (SaaS) providers and other software that ran primarily over a network were exempt (or could potentially argue exemption) from the terms of the GPL license. This is because they didn’t technically “distribute” it in the traditional sense. To close this loophole, the GNU AGPL makes it clear that network use counts as distribution of the software.